5.3.2 Prediction Model This evaluation uses point source attenuation calculation formulas and multi-source superposition formulas to predict the noise of the project. The calculation formula is as follows: L Prediction Results The predicted noise results at the project boundary are shown in Table 5.3-1. 81 Hunan Lier Circuit Board Co., Ltd. Etching Waste Liquid Recycling System Project Environmental Impact Report Table 5.3-1 Overview of Project Boundary Noise Prediction Results Prediction Points East Boundary South Boundary West Boundary North Boundary Noise Source [dB(A)] [dB(A)] Acid-Base Pump 34.7 Fan [dB(A)] Acid-Base Pump 34.7 Fan [dB(A)] Acid-Base Pump 34.7 Fan 33.2 Noise Contribution Value 34.7 Fan o div bar atm exc 式中，LA(r)——预测点 r 处的等效 A 声级，dB(A)； LA(r0)——距声源 r0 处的等效 A 声级，dB(A)； Adiv——点声源的几何发散衰减量，dB(A)； Abar——遮挡物引起的衰减量，dB(A)； Aatm——空气吸收引起的衰减量，dB(A)； Aexc——附加衰减量，dB(A)。 其中，Adiv 采用如下公式计算： Adiv  20 lg  r r  0 式中，r——预测点距声源的距离，m； 对于遮挡物引起的衰减量(Abar)，本次按照最不利情况考虑，仅考虑车间的墙体 隔声作用，隔声降噪量按 15 dB(A)计算。其它由于地形、室外建筑物等引起的衰减 忽略不计。 对于空气吸收引起的衰减(Aatm)和附加衰减(Aexc)，由于其衰减量较少，一般可 忽略不计，因此，本次对其也不进行考虑。 多源叠加公式： L Tp  101 g  n   10  i 1 LPi / 10    式中，LTP——预测点处的总声级，dB(A)； LPi——第 i 个声源在预测点处的声级值，dB(A)。 5.3.3 预测结果 项目厂界噪声预测结果见表 5.3-1。 81 湖南利尔电路板有限公司蚀刻废液循环再生系统工程环境影响报告书 表 5.3-1 项目厂界噪声预测结果一览表 预测点位 东厂界 南厂界 西厂界 北厂界 噪声源 [dB(A)] [dB(A)] [dB(A)] [dB(A)] 酸碱泵 35.5 34.7 35.5 34.7 风机 34 33.2 34 33.2 噪声贡献值 37.8 37 37.8 37 standard value daytime 65; nighttime 55. From the above table, it can be seen that the noise contribution value generated by the project at the factory boundary is relatively low. This project is an already established project, and the current monitoring data at the factory boundary is the actual value after the noise contribution value generated by this project is superimposed with the background value, reaching the Class 3 standard of the sound environment functional zoning. 5.3.4 Sound Environment Impact Prediction and Evaluation The prediction results indicate that after taking appropriate vibration reduction, sound insulation, and noise reduction measures for each noise source of the project, the predicted values at each factory boundary can meet the requirements of the "Industrial Enterprise Factory Boundary Environmental Noise Emission Standard" (GB12348-2008) Class 3 emission standard, achieving standard emissions. This project is an already established project, and the current monitoring data at the factory boundary on May 18, 2014, is the actual value after the noise contribution value generated by this project is superimposed with the background value, reaching the Class 3 standard of the sound environment functional zoning (see Table 4.4-10 in Section 4.4.5 for the statistical table of sound environment quality current monitoring results). The above predictions and actual monitoring results indicate that the noise at each factory boundary can meet the requirements of the "Sound Environment Quality Standard" (GB3096-2008) Class 3 area standard, with little impact on the surrounding environment. 5.4 Solid Waste Environmental Impact Analysis The general solid waste generated by this project, such as waste product packaging bags, is purchased by waste buyers, while waste filter cartridges and waste cation and anion membranes are recycled by suppliers for regeneration treatment, and domestic waste is collected and treated by local sanitation departments. The amount of waste filter cartridges and waste cation and anion membranes generated is 0.102t/a. During the period from when they are removed from the production line to when they are recycled by the supplier, they are temporarily stored in the hazardous waste temporary storage facility located in the northeast corner of the factory's wastewater treatment station. Due to the small amount generated, the hazardous waste temporary storage facility can accommodate it. The hazardous waste temporary storage facility passed the acceptance inspection during the acceptance of the circuit board production project. Therefore, as long as the enterprise strengthens management according to the established hazardous waste management regulations within the factory, all solid waste generated during the project operation can be effectively treated, avoiding secondary pollution and achieving "zero" emissions. The solid waste from this project will not have an impact on the environment. 5.5 Groundwater Impact Analysis The impact of the project construction on groundwater and soil environment mainly manifests in the leakage of wastewater, where heavy metal ions in the wastewater, mainly copper ions, are retained by the soil, thus changing the physical and chemical properties of the soil. To eliminate the impact of wastewater leakage on soil and groundwater environmental quality, the construction project has taken the following measures: (1) All production wastewater is connected to the wastewater treatment facilities through impermeable pipelines for treatment. After meeting the standards, it is discharged into the municipal sewage pipeline and then into the industrial park sewage treatment plant. (2) The drainage pipelines and wastewater treatment facilities have impermeable functions, cutting off the pathway for wastewater to enter groundwater. (3) The workshop of this project is located on the roof of the circuit board production workshop, with electrolysis equipment and waste gas treatment equipment installed on the steel structure foundation of the roof. An 8mm thick steel plate is laid on top, and the steel plate is treated with three layers of cloth and five layers of coating for corrosion protection, then covered with 6-8mm PP boards, and an 80mm dike is built around the workshop. A rain shed is constructed around the workshop to prevent etching liquid wastewater and electrolysis waste from leaking onto the roof; the electrolyte and acid-base liquids will not seep into the soil and groundwater. (4) This project utilizes the accident emergency pool next to the factory's wastewater treatment station to collect accident firefighting wastewater and leaked hazardous chemicals. In summary, under the premise of proposing effective and feasible control and prevention measures in aspects such as workshop design, water supply and drainage, wastewater, solid waste pollution prevention, and risk prevention, the possibility of wastewater entering and polluting the soil is relatively small, and the impact on groundwater and soil environment is minimal. 5.6 Impact Analysis of the Project on the Office Area This project is built on the roof of the circuit board production plant, and part of the second floor of the circuit board production plant is an office area. The project’s wastewater discharge will have a certain impact on the office area. 1. Impact of Waste Gas Emissions on the Office Area Due to the inability of atmospheric prediction software to predict the impact of waste gas on the office area below the exhaust stack, considering that the distance from the bottom of the exhaust stack to the edge of the building is about 10m, the predicted concentration at a distance of 10m from the exhaust stack is analyzed to assess the impact on the second-floor office area. From Table 5.1-3, it can be seen that under normal working conditions, the concentrations of hydrogen chloride and ammonia at 10m are 1.39E-11mg/m³ and 6.12E-12mg/m³, respectively; in Table 5.1-5 under abnormal working conditions, the concentrations of hydrogen chloride and ammonia at 10m are 2.79E-10mg/m³ and 3.06E-11mg/m³, respectively. It can be seen that whether under normal or abnormal working conditions, the concentrations of hydrogen chloride and ammonia at 10m are very low, with a compliance rate of 0; moreover, the second-floor office area is located to the west, while this project is located in the northeast of the third floor, and the second-floor office area is upwind of this project (the prevailing wind direction in this area is westerly throughout the year). Therefore, the impact of the project’s waste gas, whether under normal or abnormal emissions, on the second-floor office area is very small. 2. Impact of Leakage and Spillage of Waste Liquids, Regeneration Liquids, Raw and Auxiliary Materials during Project Production on the Office Area Due to the corrosive and flammable nature of the acid and alkali etching waste liquids, regeneration liquids, and raw materials such as hydrochloric acid and liquid ammonia used in the project production, any leakage or spillage will affect the personnel in the second-floor office area. During the rectification process, the floor will be treated for impermeability and diking, allowing leaked materials to quickly enter the emergency accident pool on the first floor through dedicated pipelines, preventing penetration or leakage into the second-floor office area; at the same time, the project has developed an emergency plan to quickly initiate emergency procedures in the event of a leakage accident, ensuring the safety of personnel in the office area. In summary, the impact of this project on the office area is minimal. 84 Hunan Lier Circuit Board Co., Ltd. Etching Waste Liquid Recycling System Project Environmental Impact Report Chapter 6 Environmental Risk Assessment The purpose of the environmental risk assessment is to analyze and predict the potential dangers and harmful factors existing in the construction project, as well as the sudden events or accidents that may occur during the construction and operation of the project (generally excluding human destruction and natural disasters), which may cause leaks of toxic, harmful, flammable, and explosive substances, resulting in personal safety and environmental impacts and damage levels. Reasonable and feasible prevention, emergency, and mitigation measures are proposed to ensure that the accident rate, losses, and environmental impacts of the construction project reach acceptable levels. The focus of this part of the assessment is on predicting and protecting against injuries to the population outside the factory (site) boundary caused by accidents, deterioration of environmental quality, and impacts on the ecosystem. 6.1 Risk Identification 6.1.1 Risk Identification The risk identification of production facilities mainly includes the identification of risks in production devices, storage and transportation systems, public engineering systems, environmental protection facilities, and auxiliary production facilities. (1) Risk identification of production equipment operation During the project production process, the acid and alkali liquids in the electrolysis tank and component adjustment tank are corrosive and pose a certain leakage risk. (2) Risk identification of material storage and transportation This project uses hydrochloric acid and liquid ammonia during production. The amount of hydrochloric acid used in this project is 12t/a, with a maximum storage capacity of 1t, stored together with the hydrochloric acid required for the circuit board production line in the southeast corner of the floor, with a maximum combined storage capacity of 9t, stored in two plastic barrels; the amount of liquid ammonia used is 2.4t/a, with a maximum storage capacity of 0.4t, stored in steel cylinders, 0.4t per cylinder. There is a certain leakage risk during the transportation and storage of hydrochloric acid and liquid ammonia, which may cause leakage due to tank rupture or pipeline corrosion, welding defects, etc., thus affecting the surrounding environment. (3) Other facilities The operational failure of the project's environmental protection facilities will result in the emission of air and water pollutants. 6.1.2 Determination of Material Hazardousness According to the definition of material hazardousness in the "Technical Guidelines for Environmental Risk Assessment of Construction Projects", chemicals in the project are mainly divided into three categories: general toxicity hazardous substances, flammable and combustible hazardous substances, and explosive hazardous substances. The results of the determination of material hazardousness will serve as the main basis for the classification of evaluation work levels. According to the requirements of Article 4.4.2 of the "Technical Guidelines for Environmental Risk Assessment of Construction Projects", 1-3 main chemicals involved in production, processing, transportation, use, or storage can be selected as the objects of determination based on the preliminary engineering analysis of the Environmental Impact Report for the Etching Waste Liquid Recycling System Project of Hunan Lier Circuit Board Co., Ltd. Based on the hazardous characteristics of the chemicals involved in this project and their usage and storage amounts, combined with the results of the engineering analysis, the determination basis is shown in Table 6.1-1. Material Hazardousness Determination Table Material Category Level LD50 (oral, rat) LD50 (dermal, rat) LC50 (inhalation, mouse, 4 hours) mg/L Toxic Substance mg/kg 1 <5 2 5